1. Field of Invention
This invention relates to a food composition having the ability to change its color when heated.
2. Brief Statement of Prior Art
The color of food contributes to its appetizing appearance, so much work has been done on compositions and methods for improving food color. One area of particular interest has been that of producing food products that change color upon heating. As a result, the use of principles of food science, chemistry and physics have been used in systems to effectuate the change in color of food upon exposure of the food to microwave energy or heat by conventional cooking methods. Prior art methods and compositions include:
U.S. Pat. Nos. 5,362,504 and 5,458,898 disclose an edible microwave susceptor composition and a process for applying the composition to a prepared food substrate. The composition comprises by weight 8% to 97% of an edible fatty triglycerides, 2% to 90% of a microwave absorbing polyhydric alcohol, 1% to 90% of a microwave emulsifier. The preferred emulsifier is polyglycerol esters and 10% to 30% of a microwave absorbing inorganic material. The list of these materials include titanium dioxide.
These patents also disclose that colored compositions disguised by microencapsulation, which encapsulate melts upon heating to expose the color, are known in the art (column 3, lines 38-46). However, this disclosure does not describe the composition of the encapsulate. Furthermore, it indicates that such coatings have "met with only limited commercial success". The composition requires at least 8% fat (triglycerides), as well as the presence of a polyhydric alcohol. While the use of titanium dioxide is referred to, the preferred edible inorganic material is selected from the group consisting of trisodium phosphate, sodium potassium tartrate and mixtures thereof (see the paragraph bridging columns 6 and 7). Furthermore, titanium dioxide is not part of any of the compositions exemplified.
U.S. Pat. Nos. 5,002,789 and 5,069,918 disclose a food colorant system and use of the system to color foods upon heating. The color system comprises a diluent and colorant in particle form. The color of a food is controlled by controlling the size and dilution rate of the colorant. This patent claims the color system.
The coloring system utilizes small colored particles, preferably less than 100 microns, and most preferably between 3-40 microns.
U.S. Pat. No. 5,073,392 discloses a method of forming a microwaveable food product having a preselected color. The system employs the use of Maillard reactants and programmed computer means. Maillard reactants include reducing sugars and amine sources.
The use of monoglycerides, diglycerides, titanium dioxide in food products is known in the art.
U.S. Pat. No. 3,084,050 discloses a powdered dusting composition for bakery products that includes starch, fat and titanium. The titanium is included to improve adherence of the coating, as well as to give it an attractive white appearance.
U.S. Pat. No. 3,592,940 discloses a whitening composition that comprises (1) a fatty material other than partial esters of polyols and fatty acids which have limited solubility in alcohol, (2) at least one partial ester of a polyol and (3) finely divided titanium dioxide.
U.S. Pat. No. 4,780,326 discloses a hot melt composition for the coating of meat comprising acetylated monoglycerides, paraffin and/or microcrystalline wax, cellulose ester and pigment selected from a group that include titanium dioxide.
U.S. Pat. No. 5,230,913 discloses a food product comprising particulate fat insoluble inorganic material (which can be titanium dioxide) coated with an edible fat (which can be selected from a number of fats including mono- and di-glycerides). The particle size of the titanium dioxide is less than 50 microns. No colorant other than titanium dioxide is disclosed.
U.S. Pat. No. 5,230,918 discloses a food modifying composition that can contain titanium dioxide, an edible soy fiber and an aqueous liquid. Carboxymethyl cellulose is present in amounts of about 0.01% to 0.05% (see column 7, lines 20 to 25).
U.S. Pat. No. 5,393,333 discloses a mixture comprising (a) a non-.alpha.-cellulose, (b) a colored pigment and (c) an edible plasticizer in an aqueous or organic solvent that can be used to coat a solid product.
While the prior art discloses processes and compositions for effecting color changes in food, some of these are not without problems. The use of diluents as described in U.S. Pat. Nos. 5,002,789 and 5,069,918 requires careful control of the particle size of the colorant, a diluent in particle form and a need to control the particle size of the diluent and the dilution ratio.
None of the above referred to prior art, alone or in combination, teach or suggest the specific mixture of glycerides, titanium dioxide as a coating for an edible colorant as is defined in applicant's invention